A single session of intense exercise improves the inflammatory response in healthy sedentary women.

Physical activity has a great capacity for modulating the immune system, including the inflammatory response. However, the effects of exercise on the inflammatory response have rarely been studied in women, even though women are more susceptible than men to chronic inflammatory diseases. The aim of this study was to ascertain the effect of single sessions of exercise on the inflammatory response of sedentary women, evaluating neutrophil function and circulating concentrations of inflammatory cytokines. Exercise consisted of one session of cycling (1 h at ~70% of VO₂ max) on a cycle ergometer. Blood samples were taken in the basal state and immediately after the exercise session. Neutrophil function was studied on isolated cells by evaluating their phagocytic capacity against latex beads and their oxygen-dependent microbicidal capacity as reflected in the superoxide anion (O₂⁻) production. Circulating inflammatory cytokines were determined using a novel antibody-based protein micro-array method. The circulating concentration of IL-8 (a stimulatory cytokine for neutrophils) was also determined by ELISA. Exercise increased the phagocytic and the oxygen-dependent microbicidal capacities of neutrophils in the sedentary women. No variations were found in IL-2, IL-3, IL-5, IL-6, IL-7, IL-8, IL-10, IL-13, IFN-γ, TNF-α and -β, TGF-β, MCP-2 and -3, MIG, G-CSF, and GM-CSF. However, while the circulating concentrations of GRO and MCP-1 increased after exercise, there was a decrease in that of RANTES, a pro-inflammatory cytokine. Exercise improves neutrophil function, possibly mediated, at least partially, by GRO (a potent neutrophil activator) but not by IL-8. This stimulation of neutrophil function does not seem to be accompanied by any harmful systemic inflammatory response since no changes in the main pro-inflammatory cytokines were observed, and there was a decrease in RANTES.